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libavutil/aarch64/timer.h
53 строки
2 KB
Martin Storsjö
aarch64: Use cntvct_el0 as timer register on Android and macOS
17 июн 2024, 14:00
17 июн 2024, 14:00
ab8f703
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/* * Copyright (c) 2015 Janne Grunau <janne-libav@jannau.net> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef AVUTIL_AARCH64_TIMER_H #define AVUTIL_AARCH64_TIMER_H #include <stdint.h> #include "config.h" #if HAVE_INLINE_ASM #define AV_READ_TIME read_time static inline uint64_t read_time(void) { uint64_t cycle_counter; __asm__ volatile( "isb \t\n" #if defined(__ANDROID__) || defined(__APPLE__) // cntvct_el0 has lower resolution than pmccntr_el0, but is usually // accessible from user space by default. "mrs %0, cntvct_el0 " #else // pmccntr_el0 has higher resolution, but is usually not accessible // from user space by default (but access can be enabled with a custom // kernel module). "mrs %0, pmccntr_el0 " #endif : "=r"(cycle_counter) :: "memory" ); return cycle_counter; } #endif /* HAVE_INLINE_ASM */ #endif /* AVUTIL_AARCH64_TIMER_H */